In situ photoaffinity labeling of the target protein for lembehyne A, a neuronal differentiation inducer

A C-36 linear acetylene alcohol, lembehyne A (LB-A), induces neuronal differentiation against neuroblastoma cells morphologically and also functionally. The differentiation and cytostatic effect induced by LB-A was specific to neuroblastoma, Neuro 2A cells. To identify the target protein for LB-A, a radioactive photoaffinity probe, [I-125]18-(2'-azido-5'-iodo-benzoyloxy)-LB-18 ([I-125]azido-LB-18), was synthesized. As a result of in situ labeling experiments against Neuro 2A cells, a protein of M-r 30 kDa was photolabeled specifically. This labeling was inhibited in the presence of LB-A or the active analogs of LB-A, whereas the inactive analogs showed no inhibitory effect on this labeling. These results suggest that this protein of M, 30 kDa is the target protein for LB-A and may play an important role for the neuronal differentiation in neuroblastoma, Neuro 2A cells. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.